﻿using SanlieHash.Fast;
using System;

namespace SanlieHash.GuoMi
{
    public class ZUC
    {
        internal static readonly ushort[] KD =
        {
            0x44D7,0x26BC,0x626B,0x135E,0x5789,0x35E2,0x7135,0x09AF,
            0x4D78,0x2F13,0x6BC4,0x1AF1,0x5E26,0x3C4D,0x789A,0x47AC,
        };
        internal static readonly byte[] S0 =
        {
            0x3e,0x72,0x5b,0x47,0xca,0xe0,0x00,0x33,0x04,0xd1,0x54,0x98,0x09,0xb9,0x6d,0xcb,
            0x7b,0x1b,0xf9,0x32,0xaf,0x9d,0x6a,0xa5,0xb8,0x2d,0xfc,0x1d,0x08,0x53,0x03,0x90,
            0x4d,0x4e,0x84,0x99,0xe4,0xce,0xd9,0x91,0xdd,0xb6,0x85,0x48,0x8b,0x29,0x6e,0xac,
            0xcd,0xc1,0xf8,0x1e,0x73,0x43,0x69,0xc6,0xb5,0xbd,0xfd,0x39,0x63,0x20,0xd4,0x38,
            0x76,0x7d,0xb2,0xa7,0xcf,0xed,0x57,0xc5,0xf3,0x2c,0xbb,0x14,0x21,0x06,0x55,0x9b,
            0xe3,0xef,0x5e,0x31,0x4f,0x7f,0x5a,0xa4,0x0d,0x82,0x51,0x49,0x5f,0xba,0x58,0x1c,
            0x4a,0x16,0xd5,0x17,0xa8,0x92,0x24,0x1f,0x8c,0xff,0xd8,0xae,0x2e,0x01,0xd3,0xad,
            0x3b,0x4b,0xda,0x46,0xeb,0xc9,0xde,0x9a,0x8f,0x87,0xd7,0x3a,0x80,0x6f,0x2f,0xc8,
            0xb1,0xb4,0x37,0xf7,0x0a,0x22,0x13,0x28,0x7c,0xcc,0x3c,0x89,0xc7,0xc3,0x96,0x56,
            0x07,0xbf,0x7e,0xf0,0x0b,0x2b,0x97,0x52,0x35,0x41,0x79,0x61,0xa6,0x4c,0x10,0xfe,
            0xbc,0x26,0x95,0x88,0x8a,0xb0,0xa3,0xfb,0xc0,0x18,0x94,0xf2,0xe1,0xe5,0xe9,0x5d,
            0xd0,0xdc,0x11,0x66,0x64,0x5c,0xec,0x59,0x42,0x75,0x12,0xf5,0x74,0x9c,0xaa,0x23,
            0x0e,0x86,0xab,0xbe,0x2a,0x02,0xe7,0x67,0xe6,0x44,0xa2,0x6c,0xc2,0x93,0x9f,0xf1,
            0xf6,0xfa,0x36,0xd2,0x50,0x68,0x9e,0x62,0x71,0x15,0x3d,0xd6,0x40,0xc4,0xe2,0x0f,
            0x8e,0x83,0x77,0x6b,0x25,0x05,0x3f,0x0c,0x30,0xea,0x70,0xb7,0xa1,0xe8,0xa9,0x65,
            0x8d,0x27,0x1a,0xdb,0x81,0xb3,0xa0,0xf4,0x45,0x7a,0x19,0xdf,0xee,0x78,0x34,0x60,
        };
        internal static readonly byte[] S1 =
        {
            0x55,0xc2,0x63,0x71,0x3b,0xc8,0x47,0x86,0x9f,0x3c,0xda,0x5b,0x29,0xaa,0xfd,0x77,
            0x8c,0xc5,0x94,0x0c,0xa6,0x1a,0x13,0x00,0xe3,0xa8,0x16,0x72,0x40,0xf9,0xf8,0x42,
            0x44,0x26,0x68,0x96,0x81,0xd9,0x45,0x3e,0x10,0x76,0xc6,0xa7,0x8b,0x39,0x43,0xe1,
            0x3a,0xb5,0x56,0x2a,0xc0,0x6d,0xb3,0x05,0x22,0x66,0xbf,0xdc,0x0b,0xfa,0x62,0x48,
            0xdd,0x20,0x11,0x06,0x36,0xc9,0xc1,0xcf,0xf6,0x27,0x52,0xbb,0x69,0xf5,0xd4,0x87,
            0x7f,0x84,0x4c,0xd2,0x9c,0x57,0xa4,0xbc,0x4f,0x9a,0xdf,0xfe,0xd6,0x8d,0x7a,0xeb,
            0x2b,0x53,0xd8,0x5c,0xa1,0x14,0x17,0xfb,0x23,0xd5,0x7d,0x30,0x67,0x73,0x08,0x09,
            0xee,0xb7,0x70,0x3f,0x61,0xb2,0x19,0x8e,0x4e,0xe5,0x4b,0x93,0x8f,0x5d,0xdb,0xa9,
            0xad,0xf1,0xae,0x2e,0xcb,0x0d,0xfc,0xf4,0x2d,0x46,0x6e,0x1d,0x97,0xe8,0xd1,0xe9,
            0x4d,0x37,0xa5,0x75,0x5e,0x83,0x9e,0xab,0x82,0x9d,0xb9,0x1c,0xe0,0xcd,0x49,0x89,
            0x01,0xb6,0xbd,0x58,0x24,0xa2,0x5f,0x38,0x78,0x99,0x15,0x90,0x50,0xb8,0x95,0xe4,
            0xd0,0x91,0xc7,0xce,0xed,0x0f,0xb4,0x6f,0xa0,0xcc,0xf0,0x02,0x4a,0x79,0xc3,0xde,
            0xa3,0xef,0xea,0x51,0xe6,0x6b,0x18,0xec,0x1b,0x2c,0x80,0xf7,0x74,0xe7,0xff,0x21,
            0x5a,0x6a,0x54,0x1e,0x41,0x31,0x92,0x35,0xc4,0x33,0x07,0x0a,0xba,0x7e,0x0e,0x34,
            0x88,0xb1,0x98,0x7c,0xf3,0x3d,0x60,0x6c,0x7b,0xca,0xd3,0x1f,0x32,0x65,0x04,0x28,
            0x64,0xbe,0x85,0x9b,0x2f,0x59,0x8a,0xd7,0xb0,0x25,0xac,0xaf,0x12,0x03,0xe2,0xf2,
        };
        internal static readonly uint[] EK_d =  {
            0x44D7, 0x26BC, 0x626B, 0x135E, 0x5789, 0x35E2, 0x7135, 0x09AF,
            0x4D78, 0x2F13, 0x6BC4, 0x1AF1, 0x5E26, 0x3C4D, 0x789A, 0x47AC
        };
        internal static void AddM(ref uint a, uint b)
        {
            a += b;
            a = (a & 0x7FFFFFFF) + (a >> 31);
        }
        internal static uint ROT31(uint x, int k)
        {
            return ((((x) << k) | (x >> (31 - k))) & 0x7FFFFFFF);
        }
        internal static void LFSRWithInitializationMode(uint u, ref ZUC_CTX ctx)
        {
            uint f;

            f = ctx.LFSR_S[0];
            AddM(ref f, ROT31(ctx.LFSR_S[0],  8));
            AddM(ref f, ROT31(ctx.LFSR_S[4],  20));
            AddM(ref f, ROT31(ctx.LFSR_S[10], 21));
            AddM(ref f, ROT31(ctx.LFSR_S[13], 17));
            AddM(ref f, ROT31(ctx.LFSR_S[15], 15));
            AddM(ref f, u);

            /* 更新 LSFR 生成序列 */
            for (int i = 0; i < 15; ++i) ctx.LFSR_S[i] = ctx.LFSR_S[i + 1];
            ctx.LFSR_S[15] = f;
        }

        /* LFSR 工作状态 */
        internal static void LFSRWithWorkMode(ref ZUC_CTX ctx)
        {
            ulong f = ctx.LFSR_S[0];
            f += (ulong)ctx.LFSR_S[0]   << 8 ;
            f += (ulong)ctx.LFSR_S[4]   << 20;
            f += (ulong)ctx.LFSR_S[10]  << 21;
            f += (ulong)ctx.LFSR_S[13]  << 17;
            f += (ulong)ctx.LFSR_S[15]  << 15;
            f = (f & 0x7fffffff) + (f >> 31);
            f = (f & 0x7fffffff) + (f >> 31);

            /* 更新 LSFR 生成序列 */
            for (int i = 0; i < 15; ++i) ctx.LFSR_S[i] = ctx.LFSR_S[i + 1];
            ctx.LFSR_S[15] = (uint)f;
        }
        internal static void BitReorganization2(ref ZUC_CTX ctx)
        {
            ctx.BRC_X[1] = ((ctx.LFSR_S[11] & 0xFFFF) << 16) | (ctx.LFSR_S[9] >> 15);
            ctx.BRC_X[2] = ((ctx.LFSR_S[7] & 0xFFFF) << 16) | (ctx.LFSR_S[5] >> 15);
        }
        internal static void BitReorganization3(ref ZUC_CTX ctx)
        {
            ctx.BRC_X[0] = ((ctx.LFSR_S[15] & 0x7FFF8000) << 1) | (ctx.LFSR_S[14] & 0xFFFF);
            BitReorganization2(ref ctx);
        }
        internal static void BitReorganization4(ref ZUC_CTX ctx)
        {
            BitReorganization3(ref ctx);
            ctx.BRC_X[3] = ((ctx.LFSR_S[2] & 0xFFFF) << 16) | (ctx.LFSR_S[0] >> 15);
        }
        internal static uint ROT(uint a, int k)
        {
            return ((a) << k) | ((a) >> (32 - k));
        }
        internal static uint L1(uint X)
        {
            return (X ^ ROT(X, 2) ^ ROT(X, 10) ^ ROT(X, 18) ^ ROT(X, 24));
        }

        /* 线性变换 L2(x) */
        internal static uint L2(uint X)
        {
            return (X ^ ROT(X, 8) ^ ROT(X, 14) ^ ROT(X, 22) ^ ROT(X, 30));
        }

        /* create 32-bit word */

        internal static uint MAKEU32(int a, int b, int c, int d)
        {
            return ((uint)a << 24) | ((uint)b << 16) | ((uint)c << 8) | ((uint)d);
        }
        internal static uint F(ref ZUC_CTX ctx)
        {
            uint W = (ctx.BRC_X[0] ^ ctx.F_R1) + ctx.F_R2;
            _F(ref ctx);
            return W;
        }
        internal static void _F(ref ZUC_CTX ctx)
        {
            uint W1, W2, u, v;

            W1 = ctx.F_R1 + ctx.BRC_X[1];
            W2 = ctx.F_R2 ^ ctx.BRC_X[2];
            u = L1(((W1 << 16) | (W2 >> 16)));
            v = L2(((W2 << 16) | (W1 >> 16)));
            ctx.F_R1 = MAKEU32(S0[(u >> 24)], S1[((u >> 16) & 0xFF)], S0[((u >> 8) & 0xFF)], S1[(u & 0xFF)]);
            ctx.F_R2 = MAKEU32(S0[(v >> 24)], S1[((v >> 16) & 0xFF)], S0[((v >> 8) & 0xFF)], S1[(v & 0xFF)]);
        }
        internal static uint MAKEU31(uint k, uint d, uint iv)
        {
            return k << 23 | d << 8 | iv;
        }
        internal static void Initialization(byte[] k, byte[] iv, ref ZUC_CTX ctx)
        {
            ctx.F_R1 = 0;
            ctx.F_R2 = 0;

            /* 密钥扩展 */
            for (int i = 0; i < 16; ++i) ctx.LFSR_S[i] = MAKEU31(k[i], EK_d[i], iv[i]);

            byte nCount = 32;
            //32次过程中不输出任何信息
            uint w;
            while (nCount > 0)
            {
                BitReorganization3(ref ctx);
                w = F(ref ctx);
                LFSRWithInitializationMode(w >> 1, ref ctx);
                nCount--;
            }

            BitReorganization2(ref ctx);
            _F(ref ctx);
            LFSRWithWorkMode(ref ctx);
        }
        internal static void GenerateKeyStream(uint[] pKeyStream, int KeyStreamLen, ZUC_CTX ctx)
        {
            /* working cycles */
            for (int i = 0; i < KeyStreamLen; ++i)
            {
                BitReorganization4(ref ctx);
                pKeyStream[i] = ctx.BRC_X[3] ^ ((ctx.BRC_X[0] ^ ctx.F_R1) + ctx.F_R2);
                _F(ref ctx);
                LFSRWithWorkMode(ref ctx);
            }
        }
        internal static void Next(ref uint val, ref ZUC_CTX ctx)
        {
            BitReorganization4(ref ctx);
            val = ctx.BRC_X[3] ^ ((ctx.BRC_X[0] ^ ctx.F_R1) + ctx.F_R2);
            _F(ref ctx);
            LFSRWithWorkMode(ref ctx);
        }
        internal static void Next(ref ZUC_CTX ctx)
        {
            BitReorganization4(ref ctx);
            _F(ref ctx);
            LFSRWithWorkMode(ref ctx);
        }
        internal ZUC_CTX ctx;
        internal uint now_val;
        internal uint ix;
        public ZUC()
        {
            ctx = new ZUC_CTX();
            now_val = 0;
            ix = 0;
        }

        public void Init(byte[] iv, byte[] key)
        {
            ix = 0;
            Initialization(key, iv, ref ctx);
        }
        public void Jump(int times)
        {
            for (; times > 0; --times, ++ix) Next(ref ctx);
        }
        public uint Next()
        {
            Next(ref now_val, ref ctx);
            ix++;
            return now_val;
        }
        public string NextHex()
        {
            Next();
            return NowHex();
        }
        public uint Now()
        {
            return now_val;
        }
        public string NowHex()
        {
            return FastEncode.EncodeUInt(now_val);
        }
        public long NowPos { get { return ix; } }
    }
}
